面试题29.顺时针打印矩阵
题目描述
输入一个矩阵,按照从外向里以顺时针的顺序依次打印出每一个数字。
示例 1:
输入:matrix = [[1,2,3],[4,5,6],[7,8,9]]
输出:[1,2,3,6,9,8,7,4,5]
示例 2:
输入:matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
输出:[1,2,3,4,8,12,11,10,9,5,6,7]
限制:
0 <= matrix.length <= 100
0 <= matrix[i].length <= 100
题解
没什么好说的,按题目要求来,代码如下:
class Solution {
public int[] spiralOrder(int[][] matrix) {
if(matrix.length==0||matrix==null) return new int[0];
int hs = matrix.length-1;
int ls = matrix[0].length-1;
int[] arr = new int[matrix.length*matrix[0].length];
int h = 0;
int l = 0;
int index = 0;
while(h<=hs&&l<=ls){
//向右
for(int i = l;i<=ls;i++){
arr[index++] = matrix[h][i];
}
//向下
for(int i = h+1;i<=hs;i++){
arr[index++] = matrix[i][ls];
}
向左
if(h!=hs){
for(int i = ls-1;i>=l;i--){
arr[index++] = matrix[hs][i];
}
}
//向上
if(l!=ls){
for(int i = hs-1;i>h;i--){
arr[index++] = matrix[i][l];
}
}
h++;
hs--;
l++;
ls--;
}
return arr;
}
}